The Overwatch character reveal trailer explains that Moira is geneticist with a shadowy personality. What makes her so unique when compared to her to the other heroes is that she has the ability to dish out quite a bit of damage and also heal her fellow teammates.

Moira has a Bionic Grasp ability which allows her to heal allies in front of her while her right hand can sap the health from enemies. Her Biotic Sphere heals those allies it touches yet deals damage to any enemies it passes through. Thanks to her Fade ability, Moira is also able to quickly teleport short distances. Lastly, her Coalescence ability lets her fire a long-range beam which once again heals friendly heroes but badly damages her foes.

Moira’s unique healing and damage dealing abilities are a welcome inclusion to Overwatch.